Prior to this invention various proposals have been made for modifying an internal combustion engine's conventional fuel-air supply system in order to improve fuel economy and/or to reduce engine exhaust emissions. Two examples of such modifications are described in U.S. Pat. No. 3,963,013 which issued to E. C. Authement et al on June 15, 1976 and U.S. Pat. No. 3,738,334 which issued to R. S. Farr on June 12, 1973.
In both of the patents mentioned above liquid gasoline is heated and vaporized before it is introduced into a conventional carburetor along with induction air. This is accomplished by shutting off the normal supply of liquid gasoline to the carburetor when a normal operating temperature is reached and by introducing the heated, vaporized fuel into the air stream just upstream from the carburetor's air inlet port. This type of fuel-air supply system has a number of significant drawbacks.
For one thing, the vaporized gasoline is not pressurized and occupies a relatively large volume. Second, vapor locks can occur more readily because the heated fuel is vaporized even before introduction into the carburetor. Third, re-starting the engine with the liquid fuel supply can be troublesome because the liquid fuel in the carburetor's fuel bowl tends to become depleted during the period when the liquid fuel supply to the fuel bowl is shut off.
The present invention overcomes these drawbacks as well as significantly reducing gasoline consumption and engine exhaust pollutants.